This invention relates to lasers and more particularly to conductively cooled optically pumped solid state lasers.
Laser rods and pump lamps of solid state lasers typically are cooled by liquids or gases flowing over their outer surfaces. Devices using liquid or gaseous cooling, however, are inherently complex and expensive. In addition, they have limited lifetimes due to coolant breakdown under intense ultraviolet radiation or normal wear of mechanical circulating system components. In addition, fluid cooling requires seals which complicate and increase the cost of construction, installation and maintenance of the laser assembly.
Other designs of solid state lasers use conduction cooling by connecting laser rods and lamps to heat sinks. Thermal contact in such designs is established by affixing the heat source (rod or lamp) to the sink by brazing, bonding or soldering the source to a heat sink member which generically exhibits limited pump light reflectivity. Such technique is described, for example, in U.S. Pat. No. 4,170,763. Another technique for establishing such thermal contact is pressing the heat source into, or otherwise surrounding it with a thermally-conductive medium such as a solid dielectric powder which provides heat transfer to a large heat sink. The problem with the foregoing conductively cooled systems is that they are not easily optimized. The reason is that materials having acceptable thermal and reflective properties cannot readily be optimized for both. Furthermore such materials cannot readily be brought into intimate contact with the heat/light sources over large cylindrical surface areas as required for efficient pumping and heat removal from cylindrical rods and lamps.
This invention is directed to a laser construction which overcomes these difficulties.